Ignition control device



Aug. 31, 1954 M. J. BERLYN ETAL IGNITION CONTROL DEVICE 2 Sheets-Sheet 1Filed Oct. 16, 1948 v m w M s o VLN w mm. A 36 J5 mm N A V. MR

Aug. 31, 1954 M. J. BERLYN EFAL IGNITION CONTROL DEVICE 2 Sheets-Sheet 2Filed Oct. 16, 1948 INVENTORS. BEELYN T E A M E'ENEST STANSF'IELD,

.A'TTOPNEX Patented Aug. 31, 1954 IGNITION CONTROL DEVICE Martin J.Berlyn, Enfield, Conn., and Ernest E. Stansfield, Springfield, Mass.,assignors to American Bosch Corporation,

Springfield,

Mass, a corporation of New York Application October 16, 1948, Serial No.54,973

10 Claims. 1 This invention relates to ignition timers for internalcombustion engines and has particular reference to timers of the typewhich embody a movable circuit breaker plate or supporting means.

An object of the invention is to provide a new and improved supportingmeans for the circuit breaker assembly which may be moved in angularrelation to the cam to provide variation of spark timing in relation toengine crank position. Another object of the invention is to provide apivot arrangement for the circuit breaker supporting means or platewhich will reduce to a minimum the amount of wobble of the supportingplate resulting from normal wear in said pivot which wobble may causeerratic spark timing and variations in spark timing resulting in roughrunning of the motor and in extreme cases detonation.

Another object is to provide a pivot arrangement of the type set forthabove which shall have a high length-diameter ratio and wherein the useof ball bearings is obviated.

Another object of the invention is to provide an arrangement of the typeset forth wherein the pivot for the circuit breaker supporting means isdisplaced from the cam shaft axis by such an amount that the diameter ofits pivot is entirely independent from the diameter of the camshaft andthe bearing for the camshaft.

Another object of the invention is to provide a relatively economicalyet efiicient circuit breaker supporting means.

Other objects and advantages of the invention will be apparent from thefollowing specification taken in connection with the accompanyingdrawings. The preferred embodiment has been shown by way of illustrationonly and it will be understood that changes may be made in the detailsof construction and arrangement of parts without departing from thescope of the invention.

In prior ignition timers of the type which embodied a movable circuitbreaker plate or supporting means, ithas been customary to employ abearing which surrounds the camshaft. In such constructions it has beenusual to employ ball bearings in an attempt to obviate any wobble orlooseness in the bearing which might cause erratic spark timing andvariations in spark timing resulting in rough running of the motor andin extreme cases detonation.

As ball bearings are expensive, they have added considerably to the costof such ignition timing devices and yet where attempts to avoid the useof such ball bearings have been made, the resulting constructions havenot been found satisfactory in operation because of the inherentlooseness or wobble between the parts resulting from normal wear thereofand which resulted in the various difiiculties mentioned above. Where aball bearing was not employed, the length of the pivot about which thecircuit breaker supporting plate was pivoted was limited by restrictionson the overall height of the assembly, and with the pivot surroundingthe camshaft as was previously employed, a very unfavorablelength-diameter ratio for said pivot was obtained.

We have found that by displacing the pivot for the breaker supportingplate away from the camshaft axis by an amount making the diameter ofthe pivot entirely independent from the diameter of the camshaft and itsbearing, that it is possible to obtain a satisfactory length-diameterratio of such pivot and to thereby overcome the inherent difficulty oftaking the wobble out of the pivot bearing Without the necessity ofemploying expensive ball bearings. We have found that this can besuccessfully achieved by positioning the pivot for the breakersupporting plate at such distance from the axis of the camshaft that Lthe distance between the center of the pivot and the center of thecamshaft is greater than half the sum of the diameters of the camshaftand pivot bearing but not so great as to affect unduly the amount ofcontact separation when the internupter supporting plate is movedthrough the normal timing range, yet with the camshaft and pivotbearings completely separate.

This construction is aimed primarily at ignition for engines operatingon a four stroke cycle and it is, therefore, only necessary to vary thespark timing by an angle measured at the interrupter camshaft centerequal to one-half crankshaft spark timing range as measured on theengine crankshaft. Since the timing range normally desired does notexceed thirty crankshaft degrees, then this range does not call for anadjustment of over fifteen degrees in either direction relative to theinterrupter camshaft and within this small angle the offset of the pivotfor the breaker plate from the center of the breaker camshaft causes nosignificant change in the breaker point opening. Also, where thefollower block is positioned on the midposition of advance and retard,that is, on the line passing through the centers of the breaker supportplate pivot center and the camshaft center, that the minimum variationswill be obtained.

We have also found that it is possible with such construction to providea breaker supporting plate made of a minimum amount of material 3 whichallows a maximum amount of movement of the plate and yet may beconstructed at a relatively low cost because of the amount of materialneeded and because of the small bearing required to obtain asatisfactory length-diameter ratio and also that, if desired, a lip onthe breaker plate may be providedrtoengage an undercut internalcircumferential guide in" the periphery of the.

housing for further steadying the plate and relieving the pivot for theplate of some of the bearing load.

Referring to the drawings:

Fig. 1 is a plan view of the" ignition distributor with the distributorcap removedandillustrating the invention as applied tota-di'stributorofthe engine suction control type;

Fig. 2 is a sectional view takenon line 2-2 of- Fig. 1 looking in thedirection of the arrows;

Fig. 3 is a sectional view taken on line 3---3-- of Fig. 1 looking inthe direction of the arrows;

Fig; 4-iis asection'al :view taken online 4 -4 of Fig. 1 looking-in thedirection of'the arrows; and Fig. 5 isa-plan view of thebreakersupporting plate.

Referring" more particularly to the drawings whereinsimilar referencecharacters; designatecorresponding parts throughout the several views,

the construction shown embodying the invention comprises the usual timeror'distributor housing. I in which is positioned the supportingplate 2..

which is provided with the integral peripheral spaced flanges S and thescrews' l which extend through aligned openings in the wall of thehousing l and flanges-'3 and secure the plate 2 in posi-- ofsubstantially U-shapefor the reasonthatsuch:

shape-will require a amount of material with theresultant reduction incost ofmanufacture and atthesametime allow a maximum. amount of movementfor advancin and--retard+ ing the spark.

The breaker support arm 5-is provided-with the bushing 8 which maycomprise abushing hav ing an enlarged 'headii and-'a reduced portion extending through arr-opening inthe breaker support 5 with said bushingbeingsecured in position in said openingby-brazing or other suitablemeans. The bushing-eds adapted to receive the stud Ea which may besecured to the supporting plate 2 by having a portion thereof extendingthrough anopeningin the saidsupportin plate 2 and said portionlii'being: riveted. over tosecure said stud'to said plate whereby saidstud--91], will form a pivot post for the circuit breaker'support- 5about which said support may beadjusted: foradvancing or. retarding thespark as-hereinafter described.

On the breaker support arm Eismounted the circuit breaker 'l which ismounted for pivotal movement about the pivot. II and whichhas thecontact 12 adaptedtoengage the contact l3 on..

the contact supporting bracket I4 which .is. .se-.-

cured to the breaker support 5 by the screw I5.

and adapted to be adjusted by means; of. the eccentric stud. Iii foradjusting. the relativeposition of the contacts 12 and l3; 17 may alsobe mounted on'the breaker support The spring. bracket.

4 5 for the securing thereto of one end of the circuit breaker springI8.

While one form of circuit breaker has been shown by way of illustration,it is pointed out that other types of circuit breakers might be employedsuch as the so called pivotless" type, or the contact I'3and circuitbreaker 1'-might be mounted oni=a.eseparate bracketiwherein. thecontacts l3 and I2 are positioned in permanent alignment and adapted foradjustment as a unit and said bracket ma then be secured on saidsupport5:

The circuit breaker! is provided with the usual camffollower'or strikingblock I9 adapted to engage the camnfi inithe usual manner.

On thebreakersupport 5 and adjacent the free end thereof is secured thestud 2B to which is secured one end of the'coil spring 2! and saidspring 21x hasits. opposite end secured to the stud 22 which is securedto thesupporting plate 2 and extends through. an enlarged opening-23-..adjacent the free end of-the breaker support ii.- The-open.

ing 23 should be-of such size as to allow'mo-vement of the breaker.supports-for advancingaor-v retarding the spark ashereinafterdescribed.v

A-suction device isutilizedfor advancingand retarding the spark. The.suction device. com

prises a. flexible diaphragm 24 backed up by a:- compression coil spring25-which are mounted in" the housing 26- which" is connected'to. the carfixed. tothe diaphragm, 2 3.

usual manner.

The breaker supportShas the lip 3ilwh'ich e111" gages an undercut,internal.circumferentiaLguide in theperiphery of .the housin .v I. Forconven-. ience inmanufacturethis. guide 3'l.has been. shown as formed inthe peripheral flang 3-2ionthesupport 2 although it could beiormeddirectly in the wallof. the housing. tiffdsired. Thisarrangementprovides -a constructionwherein the. breaker, support .5 i is furthersteadied and. the pivot S-relieved of some of thebearing load.

The length of the pivot. for thebreaker support. 5 and form ofthe stud.Bc'tandbirshingfiis limited. by restrictions on the overall heightofithe.as sembly and'as it is desirable. for the .pivot't'o have a' highlength-diameter ratio so asto reduc to a minimum theamount of wobbleotthe supportingplate resulting from. normal wear in. that pivot; itisnecessary, toemploy a pivot of smalldiameter. If this'pivot wereconcentric with the. camshaft; the pivot'diameterv wouldiinecessaril'ylbe greaterthan the camshaft "diameter thus g'iv-t ing a very unfavorablelength-diameter ratiofor this pivot; We"have;'..therefore; found ith'at'a favorable length diamet'er ratio can be obtainedby displacin the pivotfor the. breaker supp'orting, plate 5' away from the camshaft axis byan". amountmak'ingthe diameter of this pivot entire- 1y independent fromthe diameter ofthe camshaft and its bearing'.

The distance between the" center. ofv the" pivot".

9a and'the center offtheshaft fia for 'theicam-G should'be greater than,one-half'fthe. sum of..-the

diameters of the camshaft and pivot bearihgbfut not-so great as tounduly affct'the amount of housing I and preferably such. that: attnemidit portion of advance and retard the follower block is on the linepassing through the centers of the pivot 9a and the camshaft center.

One distinct advantage from the standpoint of reduction of cost inemploying the small pivot is that only a small bearing would be requiredeven if a ball bearing is employed and the customary large ball bearinsurrounding the camshaft, which is expensive and which also had poorlength-diameter ratio, would be eliminated.

The present construction is designed primarily for engines operating ona four-stroke cycle and it is, therefore, only necessary to vary thespark timing by an angle measured at the breaker camshaft center equalto one-half the crankshaft spark timing range as measured on the enginecrankshaft. Since the timing range normally desired does not exceedthirty crankshaft degrees, then the range does not call for anadjustment of over fifteen degrees with reference to the breakercamshaft. Within this small angle the offset of the pivot So for thebreaker support or plate 5 from the center of the breaker camshaftcauses no significant change in the breaker point opening.

On the under side of the breaker support 5 is secured the terminal clip33 to which is secured one end of the grounding lead 34 which has itsopposite end secured to the terminal clip 35 which, in turn, is securedto the upper surface of the supporting plate 2.

The coil springs 2| and normally retain the circuit breaker support 5and circuit breaker 1 in a retarded position and this is also the casewhen there is sufficient load on the engine that there will be little ifany suction exerted on the diaphragm 24 through the conduit 2'! from thecarburetor. The result is that due to this retardation of the spark, theengine does not knock during acceleration or idling or operation of theengine under considerable load. However when the operation of the engineis at sufficient speed and without tremendous load on the engine,sufficient suction will be exerted from the carburetor through theconduit 21 on the diaphragm 24 as to move said diaphragm 24 against theaction of the spring 25 and to cause the connecting rod 28 to move thebreaker support 5 to such position as to advance the spark.

From the foregoing it will be seen that we have provided relativelysimple, efficient and economical supporting means for the breakerassembly whereby said assembly may be moved in angular relation to thecam to provide variations of spark timing in relation to engine crankposition while eliminating the possibility of any erratic timing andvariations in the spark timing and rough running of the motor due to anywobble or loose movement of the breaker assembly.

Having described our invention, we claim:

1. In a device of the character described, a supporting plate having anaperture, a camshaft extending through said aperture, a cam on saidshaft and adapted to be rotated thereby, a breaker supporting memberpivotally mounted on said supporting plate, a pivot on said plate forsaid member, said pivot being eccentrically displaced and spaced fromsaid camshaft axis, a breaker contact supporting arm pivotally mountedon said breaker supporting member, a pivot for said breaker contactsupporting arm, said pivot being offset from said pivot for said breakersupporting member, and a separate adjustable contact bracket on saidbreaker supporting member and supporting a contact adjacent the contacton said breaker contact supporting arm and means on said breaker contactsupporting arm adapted to engage said cam for effecting operation ofsaid breaker upon rotation of said cam and means for automaticallyeffecting pivotal adjustment of said breaker supporting member andbreaker supported thereby as a unit.

2. In a device of the character described, a supporting plate having anaperture, a camshaft extending through said aperture, a cam on saidshaft and adapted to be rotated thereby, a breaker supporting memberpivotally mounted on said supporting plate, a pivot on said plate forsaid member, said pivot being eccentrically displaced and spaced fromsaid camshaft axis, a breaker contact supporting arm pivotally mountedon said breaker supporting member, a pivot for said breaker contactsupporting arm, said pivot being offset from said pivot for said breakersupporting member, and a separate adjustable contact bracket on saidbreaker supporting member and supporting a contact adjacent the contacton said breaker contact supporting arm and means on said breaker contactsupporting arm adapted to engage said cam for effecting operation ofsaid breaker upon rotation of said cam and means for automaticallyeffecting pivotal adjustment of said breaker supporting member andbreaker supported thereby as a unit, the distance between the center ofthe pivot for the breaker supporting member and the center of saidcamshaft being greater than half the sum of the diameters of thecamshaft and pivot bearings.

3. In a device of the character described, a supporting plate having anaperture, a camshaft extending through said aperture, a cam on saidshaft and adapted to be rotated thereby, a breaker supporting memberpivotally mounted on said supporting plate, a pivot on said plate forsaid member, said pivot being eccentrically displaced and spaced fromsaid camshaft axis, a breaker contact supporting arm pivotally mountedon said breaker supporting member, a pivot for said breaker contactsupporting arm, said pivot being offset from said pivot for said breakersupporting member, and a separate adjustable contact bracket on saidbreaker supporting member and supporting a contact adjacent the contacton said breaker contact supporting arm and means on said breaker contactsupporting arm adapted to engage said cam for effecting operation ofsaid breaker upon rotation of said cam and means for automaticallyeffecting pivotal adjustment of said breaker supporting member andbreaker supported thereby as a unit, the distance between the center ofthe pivot for the breaker supporting member and the center of saidcamshaft being at least one-half the sum of the diameters of the pivotand camshaft and not greater than the internal radius of the housingcontaining the support.

4. In a device of the character described, a supporting plate having anaperture, a camshaft extending through said aperture, a cam on saidshaft and adapted to be rotated thereby, a breaker supporting memberpivotally mounted on said supporting plate, a pivot on said plate forsaid member, said pivot being eccentrically displaced and spaced fromsaid camshaft axis, a breaker contact supporting arm pivotally mountedon said breaker supporting member, a pivot for said breaker contactsupporting arm, said pivot being offset from said pivot for said breakersupporting; member; and a: separate adjustable contact bracket ron saidbreaker supportingmems berr and supporting .a' conta'etaadjacent" thecontactzon said breakercontact supporting arm and means :-on saidbreaker: contact-supporting arm adapted to: engage saidicam foreffecting operation 'ofsaidabreakerxupon rotation of said cam and meansfor automatically efiecting pivotal adjustment .of said breakersupporting. member an'cliubrealzer;- supported thereby as -a unit, saidbreaker supporting member: having a peripheral portiomengagingeaportion'zrof theperiphery of.-

th'e'shousin'g .for further: steadying said '.member.

5.? An ignitionwtiming, device for anengine includinga housing, 'a'rotary cam'sin said housing, asupportwcarriedby said'housing,artimingplate pivotedsonisaid support: in an'. axis that is ecs centricwithi' respect to thecaxis of. the; cam and at'iaztgreaterz'distancesthan theimaximum. radius of..said:'cam;anxig-nition timing? circuit breaker provided with :an' element :adaptedto periodical- 1y; engagezthe cam to openzthecircuit breakerv mounted onsaid timingplate with .said 1 element located diametrically opposite tothe .plate pivotal 4 point with 2 respect to the. camsaxis;

6:..An1igni-tion timingtdevice i or an engine. including ;a housing, arotary Vcam' inxsaidihousing, ausupport carried by saidhousing, anignition timing circuit 1 breaker including a .cam follower, meanspivoted on said-support ata point located outsiderot the maximumradius-ofathe. cam: formoving saidicircuit-breaker and cam follow-erwithrespect. tothe cam, a. device'converting' engine suctionxintomovement connected to said means for moving the same, the arrangementbeing such that the point of application of force produced by said:device: tosaidmeansis diametrically opposite: to its pivotal point withrespect .tothe cam axisiand the distance of the pivotal .pointlfrom thecam axis issgreater than theirdis'tance of the cam engagingface of saidfollowerifrom the cam axis.

7; An ignition :timingdevice for an :engine includ-iznga housing, arotary cam in said housing, a circuit breaker system having: a camfollower,

as. pivoted; ignition" timing plate.- for 'suppoorting' saidzicircu-itbreaker system; the pivotal point of said timing. plateebeingalocatedoutside ofthe perimeter-sot the cam; a'.spring-loaded suctionresponsive?device. connected with said plate for m'oving the'samewith respect tosaid rotarycam for changing the movement to the circuit breaker camfollower, the arrangementbeing such with respect to'the cam-"axis thatthe movementof the circuit cam ignition timing imparting s: followertakes place in an area diametrically op.- posite to the pivotal point,and the point of con:-' nection of the plate with the suction-responsivedevice is located at a greaterdistance from-the camraxis than thedistance of the circuit breaker:

canr'iol-lower therefrom.

8.v .An ignition timing device for an engine including a housing; arotary cam in said housing, a support carried by said housing, a timingplate pivoted-onsaid. supportin'an' axisthat is eccentric with respectto the aXi'sJof the cam and .at a

greater ldistance than the maximum cam radius of said cam, an ignitiontiming circuitbreaker:

provided with an element adapted to periodical- 1y. engage the cam to.open the circuitbreaker mounted on said timing plate with said elementlocated diametrically opposite to the plate cam. axis, and meansforinitially setting the breaker systemcam follower on said timing plate atazpointslightlydisplaced from a plane passing through the point ofapplicationioi force of the vacuum-actuated devicerand theplate pivotalpoint.

10. An ignition timing'assembly comprising a relatively stationarysupporting member having acentralaaperture, a movable-ignition timingplate, means. for mounting said timing .plate on said supportingmember'at a pivotal point spaced.

from? the aperture of the supporting member, a motion-transmittingdevice connected to the timing plate adjacent its outer periphery, andthe saidzpivotal point and-l thev said pointiof connec-- tion of themotion-transmittingdevice with said plate being, diametrically oppositeand located" at difierent radial (41151381110365'fIOm thE CBIItBI of thesupporting member;

References (liteddnthe fileof this patent UNITED STATES PATENTS- NumberName Date.

1,445,261 Anderson Feb. 13,1923 2,035,621 Smith Mar. 31,-.1936 2,290,078Thomas July 14, 1942. 2,348,236 Arthur May 9, v1944. 2,508,486 Berlyneta1. May. 23, 1950

